1. Field of the Invention
The present invention relates to a sheet processing apparatus such as a scanner, a copying machine, a printer or a facsimile apparatus having means for reading an image of an original and/or forming an image on a sheet, and in particular, to a sheet feeding apparatus for feeding a sheet which is provided in these apparatuses.
2. Description of the Related Art
As an example of a conventional sheet processing apparatus of this type, an image reading apparatus is shown in FIGS. 9 and 10.
An image reading apparatus 40 has a configuration in which an upper original guide 46 that is a rotatable upper frame forming an upper part of a main body of the image reading apparatus 40 and a lower original guide 102 that is a fixed lower frame forming a lower part of the main body (hereinafter referred to as conveying frame) are combined and an original conveying path is formed between the upper original guide 46 and the conveying frame 102.
The conveying frame 102 is provided with a sheet feeding roller 103 that receives driving force transmitted from a not-shown motor to feed an original D from an original tray 101 on which a sheaf of originals is stacked to a download side of an original conveying direction, a contact image-reading sensor (hereinafter referred to as CIS) 110 for reading image information on the original D, a conveying roller 107 for conveying the original D to the CIS 110, a discharge roller 109 for discharging the original D, and the like. In addition, a separating pad 105 for coming into contact with the sheet feeding roller 103 to separate originals one by one from the sheaf of originals, a conveying roller 106 for into contact with the conveying roller 107 to convey the original D to the CIS 110, a discharge roller 108 for coming into contact with the discharge roller 109 to discharge the original D to a discharge port 114, and the like are arranged on the upper original guide 46.
A plurality of pieces of originals D set with their reading surfaces facing downward on the original tray 101 are separated and conveyed one by one from the one at the bottom by the sheet feeding roller 103 and the separating pad 105. The separated original D is conveyed to the CIS 110 by the conveying roller 107 and the conveying roller 106. When the original D passes the CIS 110, an image is read and the original D from which the image is read is discharged to the original discharge port 114 by the discharging roller 109 and the discharging roller 108.
The separating pad 105 is held by a pad holder 31, which is attached to the upper original guide 46. The pad holder 31 is rotatable and configured to come to be in pressured contact with the sheet feeding roller 103 by a coil spring 51 at a predetermined pressure.
FIGS. 10(a) and 10(b) are views showing the back of the upper original guide that is removed from the image reading apparatus. A method of attaching the pad holder 31 holding the separating pad 105 to the upper original guide 46 will be described with reference to FIG. 10. An opening 47 for embedding the pad holder 31 is formed in the center of the upper original guide 46.
Shaft fitting portions 48 and 49, in which outer portions of rotating shafts 32 and 33 of the pad holder 31 can be fitted are provided on both side portions of the opening 47 on the back of the upper original guide 46.
The shafts 32 and 33 are fitted in the shaft fitting portions 48 and 49 from the back of the upper original guide 46, whereby the pad holder 31 is attached to the upper original guide 46.
However, in the case of the above-mentioned prior art, there are problems as described below,
A separating pad unit (a unit incorporating separating means consisting of the separating pad 105 and the pad holder 31) is attached from the back of the upper original guide 46 in a state in which the back of the upper original guide 46 is opened by removing an armor attached to the upper original guide 46. Thus, it is difficult to insert the separating pad unit and a worn separating pad unit is poorly replaceable.
The present invention has been devised in view of the above and other drawbacks of the prior art, and it is an object of the present invention to provide a sheet feeding apparatus and a sheet processing apparatus in which improvement of usability as well as improvement of sheet feeding performance are realized.
In order to attain the above-mentioned object, the present invention provides a sheet feeding apparatus that is comprising
a sheet conveying rotational member that is rotated in a feeding direction of sheets;
a separating unit having a frictional member for abutting the sheet conveying rotational member to form a nip portion; and
a frame body having an opening in which the separating unit is accommodated and holding the separating unit,
wherein said sheets can be separated and fed one by one by the nip portion, and
which is characterized in that an insertion guide for guiding insertion of the separating unit into the opening from the sheet conveying rotational member side; and
a position regulating portion provided in the edge area of the opening and regulating a portion to be regulated, which is provided in the separating unit guided by the insertion guide to be inserted in the opening, to locate the separating unit in a position inside the opening where the separating unit should be accommodated are provided in an edge area of the opening.